Argonautes compete for miR165/166 to regulate shoot apical meristem development

Plant stem cells in the shoot apical meristem (SAM) possess the unique abilities of both self-renewal for SAM maintenance and providing undifferentiated daughter cells for initiation and subsequent development of aerial organs. The coordination between stem cell renewal and cell differentiation during organogenesis is regulated by elaborate genetic pathways involving numerous transcription factors and other molecules. In the past decade, microRNAs (miRNAs) have emerged as pivotal regulators in many biological processes including meristem homeostasis and differentiation in plants. In this review, we summarize current knowledge about the function and mechanism of a family of miRNAs (miR165/166), the miRNA-designated Argonautes (AGOs), and the miRNA-regulated targets in SAM development and maintenance.

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► SAM is the ultimate source aerial organs.
► HD-ZIP III genes positively regulate SAM development.
► miR165/166 target HD-ZIP III transcripts.
► Both AGO1 and AGO10 bind to miR165/166 to regulate HD-ZIP III transcripts, but their modes of action are opposite.
► AGO10 competes with AGO1 for miR165/166 to regulate meristem development.